This invention relates generally to a ride control system for a machine and more particularly to a control system for selectively providing a cushioned ride control.
In known ride control systems for machines, cushioning of the ride is controlled by an accumulator or accumulators connected in parallel to the actuator cylinders. In such machines having a bucket or such on the front or back thereof, there is a possibility that the machine will lope or bounce due to the weight of the bucket reacting to the machine traveling over rough terrain or other obstacles. It is desirable to selectively activate the ride control and not permit the bucket to have any degree of movement from its initial position and to permit any pressure in the accumulator to be bled down when the machine is shut down. Known ride control systems are often complex and give the actuators/cylinders a spongy feeling.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a hydraulic ride control system is provided and adapted for use in a fluid system of a machine to cushion the ride of the machine in response to initiation of a ride control mode command. The machine includes a frame with an actuator arrangement disposed between the frame and a load to raise and lower the load relative to the frame. The actuator arrangement has a raise port and a lower port and is operative upon initiation of a raise mode command to raise the load to a desired height in response to pressurized fluid being selectively directed to the raise port from a source of pressurized fluid and to exhaust fluid from the raise port to a reservoir in response to initiation of a lower mode command. The hydraulic ride control system includes an accumulator arrangement connectable to the raise port of the actuator arrangement, a first valve arrangement and a second valve arrangement. The first valve arrangement is connectable between the lower port of the actuator arrangement and the reservoir and operative to selectively connect the lower port to the reservoir in response to initiation of a ride control mode command. The second valve arrangement is disposed between the accumulator arrangement and the raise port of the actuator arrangement and operative to selectively connect the accumulator arrangement to the raise port of the actuator arrangement in response to one or both of the initiation of the raise mode command and the initiation of a ride control mode command.